1. Field of the Invention
This invention relates generally to pneumatically actuated percussive tools, and more specifically, this invention relates to a pneumatically actuated percussive tool which may be energized by a bottled pressurized gas, with specific reference to its use as a rescue tool.
2. Description of the Prior Art
Pneumatically actuated tools have been used for a large variety of purposes, such as paving breakers, rock drills, coal mine stopers, chipping hammers, boulder breakers, etc. Accordingly, there has been a great deal of developmental work done over a period of many years to enhance and adapt these pneumatic tools for specific applications. However, these developmental efforts have not included a tool that meets the requirements for use in emergency rescue situations, such as those encountered by firemen and emergency rescue teams.
One of the requirements of a tool for use in the emergency rescue area is that it be relatively small, since the rescuer frequently has to operate in a limited space. Along the same lines, the rescue tool should be relatively light and maneuverable, since the operator may not only be faced with a limited space, but may also be forced to maneuver from awkward positions or rapidly shift from one area to another.
As it would be very difficult to drag along a compressor, and as the time necessary to get the compressor started and producing the requisite pressure could be vital, it is preferable that the tool be capable of operating from pressurized gas maintained in a suitable container, frequently referred to as "bottled" gas. Since the rescue tool will be called upon to perform a variety of different functions, it would be helpful if the tool could be adjusted to provide blows of differing force, for these different applications.
Since potentially combustible fumes are frequently encountered in emergency rescue work, the use of a pneumatically driven rescue tool, rather than an electrically driven tool, has certain safety advantages. (In this regard, it should be noted that the term "pneumatic" is used herein to encompass both the use of air and the use of other driving gases. Normally, compressed air would be the driving gas, although in some applications some other type of driving gas might be preferable.)
Prior art pneumatic devices are not capable of satisfying the requirements for use in emergency rescue work, although various attempts have been made to deal with one or more of these requirements. Therefore, a pneumatic rescue tool that can satisfy the rigorous requirements in emergency situations is needed.